Method of forming gears



June 11, 1929.

o. HOVEY IETHOD OF FORMING GEARS Filed Oct. 15. 1927 2 Sheets-Shee 1 I N VQV TOR.

ATTORNEYS.

June 11, 1929. HOVEY 1716.637

Sheets-Sheet 2 Patented June 11,1929.

omrso STATES PATENT oFFicE.

oscr'm n. HOVEY,

O2 DETROIT, MICHIGAN, ASSIGNOR TO FOBI) MdTOB COMPANY, OF

HIGHLAND PARK, MICHIGAN, A CORPORATION OF DELAWARE.

METHOD OF FORMING GEARS.

Application filed October 15, 1927. Serial No. 226,305.

The object of my invention is to provide a method of manufacturing chamfered gears which is practical, convenient, and economical.

Still a further object of m invention is to provide a method of chamfermg a gear wherein the chamfer'ing may be done in a die in a coining press as distinguished from being milled or machined.

Still a further object of my invention is to I provide a process for forming a chamfer at the ends of gear teeth wherein the chamfering may be done in a coin press die after the tooth has been rough machined-but before the finishing operations, whereby the heat used for heat treating the gear following the rough machine operation may be utilized at the time the chamfer is formed on the teeth and said heat may also be used for drawing or annealing any strains set up in the teeth due to the chamiering thereof in the coin press dies.

With these and other objects in view my invention consists in the arrangement, construction, and combination of the various parts of my im roved process by which the method of forming the gear is accomplished,

ill

as described in the specification, claimed in the claims, and illustrated in the accompanying drawings, in which Figure 1 shows a plan view of a gear made in accordance with my invention.

Figure 2 shows a side elevation of the gear shown in Figure 1'.

Figures 3, a, and-5 show enlarged detail elevations illustratin the three steps in the forming of the chem cred teeth used in connection with my improved gear, and

Figure 6 shows a vertical central sectional view illustrating the gear blank and the coin press dies for forming the chamier thereon.

Referring to the accompanying drawings 1 have used the reference numeral 10 to indicate generally the completed gear which I have devised and which has been formed by my improved method. This gear has a plurality oi teeth 11 which are chamfered at one end as is illustrated at 12.

The gear is initially roughmachined out i to :iorm the teeth with the square ends illuswhereby it may be hardened, and while the gear blank is hot, it is struck with the coining press dies illustrated in Figure 6 to-thereby' put the chamfer illustrated at Figure 4 of the ends of the teeth 11. Followingthe chamfer and the heat treating operations, the teeth are then given the finish treatment wherebv the completed teeth shown inFigure 5 are secured and the gear illustrated in Figures 1 and 2 is formed.

The coin press operation is illustrated in Figure 6, wherein the platen 13 of the coin press has a head 14 movable toward and from said platen. A holding die 15 is clamped to the platen 13 by the screws 16 and located thereon by the dowel 17. This die has a recess therein designed to receive the end of the gear blanks which are to be chamfered, and the pilot pin 18 is provided in the die 15 to insure that the teeth of thesblank 10 will be properly positioned. The chamfering die 19 is clamped to the head 14 by the screws 16 and located relative thereto by the dowel 17.

This die is so formed that it rounds oil the upper end of the teeth on the blank to the form shown in Figure 4 when the press is operated to brin the dies 15 and 19 together. After the ends 0 the teeth have been rounded in the dies, the gear is allowed to cool and then is given its final form by cutting thefinish cut on the teeth so that it will appear as illustrated in Figures 1 and 2.

Among the many advantages resulting .85 from the use of my improved gear and the method of forming same, it should first be pointed cut'that ordinarily the ends of the 1 gear teeth are rounded or chamiered by machine operations which are tedious and expene0 sive, for instance it would take five machines of the t y e ordinarily used for the producing cham ers working a full eight day to produce the same number of chanoifered Pears that l am enabled to produce with a single coining ress. Where the character is machined t e-tough exterior surface oi the gear is mac ined away leaving the comparatively open and porous interior structure of the gear tooth metal exposed to the shock of meshing the gears. With my improved method, however the grain structure of the gear is improved at the point of contact instead of being deteriorated. That is, the operation of the die tends to compact the structure the matelos rial at. the chamier or meshing end or": the gear teeth and thereby strengthen same.

Still a further advantage results from the use of my improved process, in that I am enabled to chamier the gear teeth in a coining no press while the gear is hot at the time when it has been heated for the purpose of heat treatting between the rough and finish operations, so that no additional heating of the blank is re uired for accomplishing my process.

ome changes may be made in the shape of the blank and the method of shaping same without departing from the spirit of my 1m-' proved imzention and it, is my intention to cover by in claims such changes as may reasonably be included. Within the scope thereof.

1 claim as my invention: 1. The method of forming gears having chamfered teeth, consisting of rough machining the gear to initially form the teeth, then heating the gear and striking same with a die to chamfer the ends of the teeth, and then finish machining the gear teeth.

2. The method of forming gears with chamfered teeth, consisting of initially forming the blank, then machining teeth thereon, then strikin the ends of the teeth with a die to form t e chamfer thereon, and then finish 

